Hickey roller and method

ABSTRACT

A VERY EFFECTIVE AND LONG-LIVED HICKEY ROLLER HAS A SMOOTH ROLL SURFACE OF COMPRESSED FELTED FIBERS WITH A DENIER LESS THAN 3, BONDED TOGETHER BY BINDER, WITH AT LEAST THE OUTER PORTION OF THE SURFACE POROUS TO PRINTING INK. SMOOTH CHARACTER CAN BE PROVIDED BY HELICALLY WRAPPING A RELATIVELY NARROW SHEET OF THE FELTED FIBERS AROUND A ROLL CORE AND CEMENTING IT IN PLACE UNDER PRESSURE WITH THE HELICAL EDGES CAREFULLY BUTTED TOGETHER. ALTERNATIVELY A SHEET SUFFICIENTLY WIDE CAN BE CIRCULARLY WRAPPED SEVERAL TIMES AROUND THE CORE, CEMENTED IN PLACE AND THEN GROUND TO A UNIFORM CYLINDRICAL SURFACE. RAISING OF A LITTLE NAP OF THE SURFACE IS HELPFUL.

y 20, 1971 w. D. BUDINGER 3,594,255

HICKEY ROLLER AND METHOD Filed on. 16, 1968 United States Patent 3,594,255 HICKEY ROLLER AND METHOD William D. Budinger, Wilmington, Del. (Rte. 1, Box 469D, Chadds Ford, Pa. 19317) Filed Oct. 16, 1968, Ser. No. 767,980 Int. Cl. B31c 13/00; B65h 81/00; B41f 35/04 US. Cl. 156-425 12 Claims ABSTRACT OF THE DISCLOSURE A very effective and long-lived hickey roller has a smooth roll surface of compressed felted fibers with a denier less than 3, bonded together by binder, with at least the outer portion of the surface porous to printing ink. Smooth character can be provided by helically wrapping a relatively narrow sheet of the felted fibers around a roll core and cementing it in place under pressure with the helical edges carefully butted together. Alternatively a sheet sufficiently wide can be circularly wrapped several times around the core, cemented in place and then ground to a uniform cylindrical surface. Raising of a little nap on the surface is helpful.

The present invention relates to hickey rollers, which are rollers used in the inking of printing plates or the like.

The offset printing industry has long been plagued with the appearance of small blemishes or spots on the finished copy. These defects, called hickeys by printers, are usually caused by foreign particles such as dirt, bits of paper or dried ink which get into the inking train and from there onto the plate then interfere with proper ink transfer. Heretofore the only sure method of removing the foreign particle has been to stop the press and physically scrape the offending particles off the plate.

Some measure of during the run protection had been available through the use of specially prepared inking rollers, called hickey rollers. Sleeves of polytetrafiuoroethylene or other fiuorinated plastics, rubber compounded with such plastics, rubber compounded for porosity with blowing agents or dissolved-out materials, or rubber given a flocked fibrous surface, have all been tried on inking rollers with only limited success. The most effective spotremoving roller available to date is probably the oldest. It is made by sewing heavy leather into a sleeve and then fitting this sleeve over a hard (80 Shore A durometer) rubber-covered roller core. The foregoing roller surfaces seem to collect and render innocuous foreign particles that may arrive through the inking train or that find their way onto the inked portions of the plate.

Although the best heretofore available, the leather roller is plagued with many disadvantages. It is difficult to clean, gets hard and scratches the plates, and the cover must be frequently retightened.

Among the objects of the present invention is the provision of novel hickey rollers that are not only highly effective but have long maintenance-free lives.

Additional objects of the present invention include the provision of inking trains containing the novel rollers as Well as improved techniques for making such rollers.

The foregoing as well as further objects of the present invention will be more fully understood from the following description of several of its exemplifications, reference being made to the accompanying drawings in which:

FIG. 1 is a perspective view of one end of a hickey roller embodying the invention;

FIG. 2 is a vertical sectional view of a sheet that can be used to make such a roller; and

FIG. 3 illustrates an inking train in which a roller of the present invention is incorporated.

According to the present invention a hickey roller has a smooth roll surface of compressed felted fibers with a denier less than 3 bonded together by a binder, at least the outer skin of the surface being porous to printing ink.

Referring to the drawings, the roller 10 of FIG 1 has a fibrous sleeve 12 firmly cemented on a rubber core 14 which is in turn mounted on a solid or hollow shaft 16 that may be made of a metal like steel or aluminum. The

rubber core 14 is preferably an oil-resistant rubber like The sleeve 12 is made of a sheet of felted fibers (hereinafter called the substrate) such as described in Example 1 of US. Pat. 3,067,483 granted Dec. 11, 1962, but needlepunched from a thicker mat so that it has a thickness of 0.075 inch. The remainder of the procedure of that example is followed up until the buffing step. Instead of bnffing, the substrate is then trimmed into the form of an elongated strip with parallel side edges, the-core is coated with a flexible adhesive, and the strip helically Wrapped around the coated core. A helix angle of about 40 to 50 with respect to the axis of the core is very suitable. Care is taken during the wrapping to have the abutting edges of the substrate free of adhesive and in uniformly close engagement with each other throughout the wrap. The assembly is then placed under radially directed pressure until the adhesive is fully cured.

It is helpful to seal the sheet surface which comes in contact with the adhesive as by coating the surface with a layer that renders it effectively non-porous and thus keeps the adhesive from soaking into the sheet. One very desirable sealing technique is to spread on the sheet a 0.005 inch thick coating of a butadiene-acrylonitrile rubber mixture as follows (in parts by weight):

100 parts uncured butadiene-acrylonitrile rubber such as Hycar 1032 5 parts zinc oxide 1.5 parts sulfur parts carbon black 1.5 parts benzothiazyl disulfide 1 part stearic acid 800 parts dry methyl ethyl ketone and then curing the rubber by passing the coated sheet through a curing oven maintaining a dwell of 10 minutes at a temperature of 280 F. The cured sheet is then slit into a strip having a width equal to 2.2 times the diameter of the roller to be covered. It is now ready to be wrapped on the adhesive-coated roller.

The adhesive used may be any one of the well known and commonly available rubber-bonding adhesives. Because the substrate offers excellent opportunity for mechanical bond, it is only necessary to match the adhesive to the particular type of rubber on the roller being covered. A flexible epoxy adhesive is particularly effective for bonding the substrate to most commonly used rubber cores. An adhesive of this type is made by mixing 60 parts by weight of a low molecular weight epichlorohy drin-bisphenol A condensate with 40 parts by weight polyamide condensation of dimerized coconut oil acids with triethylene tetramine (equal parts) and 50 parts by weight of methyl ethyl ketone. When such a solvent-containing adhesive is used the solvent is permitted to evaporate before proceeding. A suitable epichlorohydrin-bisphenol A condensate is available from Shell Chemical Co. as Epon 828, and a suitable polyamide condensate from the same company as V-25 curing agent. The surface of the rubber core is preferably prepared for receiving the adhesive by wiping it with a solvent like methyl ethyl ketone or acetone or methylchloroform.

Using the prepared substrate with the sealed side toward the adhesive, the roller is helically wrapped using great care to butt seams tightly together. Start and finish points may be temporarily held down with adhesive tape. To ensure a complete and tight bond, a pressure overwrap is applied by a 3% inch wide nylon curing tape having a minimum tensile strength of 150 pounds per linear inch and also helically wrapped. This operation is greatly simplified if the roller is rotated in a lathe while tension is applied. The pressurizing tape is Wound dry over the substrate, oppositely helixed, using 200 to 300 pounds tension and 67% overlap. This method creates considerable force holding the butt joint closed and results in an invisible seam in the finished product.

Curing of the epoxy adhesive is carried out for 48 hours at room temperature, but can be shortened by using higher temperatures.

The curing pressure can be applied by a toroidal ring of flexible rubber or other air-impervious material fitted with an air valve like an automobile tire tube. The ring has a central diameter into which the wrapped core is inserted with its axis aligned with the toroidal axis, after which the ring is inflated to cause the wrapped core to be squeezed. A pressure of about 50 pounds per square inch is very eifective. Curing is completed in about twentyfour hours, and can be hastened by heating to temperatures of 120 to 250 F. During the pressuring and curing care should be taken not to permit any shifting of the wrap.

When the curing tape is used for pressurizing, higher pressures may be obtained by dampening the tape with water before wrapping and allowing it to dry and shrink after wrapping. Excessive pressure may cause irreversible crushing of the substrate, and is preferably avoided although such a crushed substrate can still be used.

The cured roller is removed from the pressurizing and should not show excess adhesive. It can now be inserted in the inking train, as by fitting its shaft in the roller journals of an inking train. It is preferred however to dress the cured hickey roller, as by subjecting it to a grinding operation that removes a small amount, 0.015 to 0.020 inch, of the surface and assures its accurate cylindrical shape. The grinding is easily eifected with an ordinary carborundum grinding wheel mounted on a lathe or roll grinder in the manner customary to the rubber roll-making industry.

For best results the sleeve 12 should be further impregnated with additional binding agent to improve both its operating life and function. Polyurethane and polyurea impregnants are particularly desirable in this respect. The following impregnant is a highly eifective one:

100 parts polyurethane of tetramethylene ether glycol and toluene diisocyanate with an available isocyanate content of 4.10%

12.5 parts 4,4-methylene-bis-(2-chloraniline) 0.2 part adipic acid 300 parts anhydrous acetone.

About five minutes are required to thoroughly saturate the substrate, after which the roller may be removed and the acetone allowed to evaporate.

. Any other flexible resin used in synthetic leathers makes a suitable impregnant when dissolved or dispersed to provide an impregnating composition of low viscosity. The total weight of non-volatile impregnant in the sleeve is preferably about equal to the weight of the fibers themselves although it can vary from about to about 75% of the total weight of the impregnated substrate.

The binder can be a resin that has a tensile strength exceeding 1200 psi. when fully cured. Lower tensile strengths are not desirable. The binders must be curable at temperatures that do not deleteriously affect the fibers or the roller core when such a core is used. Typically the cure temperatures should be under 300 F. and just about all resins meet this condition. The binder should also be resistant to inks and solvents normally encountered in offset printing. Elastomeric binders are much to be preferred as compared With non-elastomeric ones, and they may be thermoplastic or thermosetting. Impregnating compositions that have a viscosity greater than 5 poises do not penetrate well into the substrate and are accordingly not desirable. Concentrations as high as 20% binder can be present in the impregnating composition, preferably dissolved in low viscosity diluents such as acetone. Resin suspensions can also be used as impregnating compositions.

After the solvent or suspending medium has evaporated from the impregnated substrate the binder is cured and the roller may be given its final dress grinding. Curing of the foregoing binder may be accomplished in seven days at room temperature but is preferably conducted for three hours at 212 F. The intermediate grinding can be omitted where there is a finish grinding.

The final grinding process leaves a very fine nap on the roller surface. It is generally desirable to enhance this nap as by turning the roller in a lathe at 750 to 1000 rpm. and bufiing the surface lightly with #100 grit aluminum oxide paper. The direction of rotation is best reversed with each pass of the paper until at least five passes have been made.

The product of this example has no visible seam. It has a soft downy feel in spite of an apparent surface hardness of 6575 durometer Shore A. When properly installed on a wet-offset press in the first inking position over the plate, its hickey-removal action is of outstanding superiority and its surface texture does not print through to the work. It seems to have little or no tendency to scratch or abnormally wear the plate and, surprisingly, it can usually be cleaned of ink using a normal inpress wash up.

The substrate 12 is preferably at least 15 mils thick to provide the desired hickey removal. The thickness can be substantially greater than 15 mils and as much as /2 inch or more, but the effectiveness of the roller does not improve significantly after the thickness is increased beyond about mils. The fibers can be of any kind, either hydrophilic, hydrophobic, oleophilic or oleophobic. The desired porosity with respect to printing inks can be obtained with any of these types of fibers such as polyamide, polyimide, polyester, protein for example wood or silk, polyesteramide, regenerated cellulose, cellulose acetate, cellulose nitrate, cellulose butyrate, asbestos, rayon, linen, cotton, ramie, batasse, hemp, rubber, metals, or glass. The more durable and wear-resistant fibers such as polyamide, polyethyleneterephthalate and polyacrylonitrile are preferred,

It is also desirable to have the fibers securely felted together so that they better withstand the flexing the substrate undergoes in use. Crinkled fibers that are very thin and at least A1 inch long, preferably at least /2 inch long, before crinkling are used for this reason. The crinkling can be carried out by heat processing, with or without solvent, by mechanically curling or in any other effective Way, and the fibers can have a cross-section that is circular, elliptical, fiat or even crescent-shaped, the latter shapes enabling more drastic crinkling. The felting of the fibers together can be accomplished by needle-punching batts as in the above example, or they can be wet-felted like paper is, or dry-felted like mens hat are.

In general the substrate does not have to have any binder when it is first wound on the core or shaft, but the presence of a little binder, even 5% by weight of the fibers, strengthens the sheet and makes it easier to wrap as well as keep aligned.

Fibers at least /2 inch long, measured in uncrinkled form, should be used for needle-punching.

The substrate of the present invention has sufficient resiliency so as to provide good hickey-picking even if held on an unyielding core. For such purposes it is desirable to have the substrate at least 80 mils thick directly adhered to a wood or metal core for example.

The use of a yieldable core has advantages, particularly when the yieldability corresponds to the 20-50 durometer hardness referred to above.

The presence of a seam or other interruption in the uniformity of the outer surface of the sleeve is undesirable since such interruption will frequently print through to the fiinished work. It is for this reason that care should be taken to accurately abut the edges of the substrate used to form the sleeve. When the substrate used to form the sleeve has a thickness as high as 8% or so of the outer radius of the core, the spiral winding tends to cause the outer surface of the sleeve to be stretched and pull the side edges toward each other. This has the effect of giving these edges a bevelled appearance and prevents the edges from being butted together over their entire depth. This diiriculty can be minimized by giving the side edges an initial reverse bevel. FIG. 2 illustrates a strip 18 of the substrate of the present invention with reverse tapers 20 at the side edges extending between the outer surface 21 and the inner surface 22. Bevels 20 of as little as 10 to 20 measured away from perpendicularity with respect to the outer and inner surfaces, are adequate in most cases to permit accurate abutting of sheets 40 to 200 mils thick and the preparation of a sleeve that shows no seam, particularly after a light grind dressing.

A seamless construction can also be provided by wrapping several turns of the substrate in an unhelixed manner around the core. The leading edge of such a wrapped sheet can extend parallel to the cores longitudinal axis and the trailing end of the last turn can extend far enough to overlie the leading end. Cementing the above wrap in place on the core as well as cementing the turns to each other followed by a grinding to make the external surface truly cylindrical, will provide all the characteristics of a seamless surface. If the adhesive is the same as the binder, the ground juncture at the trailing end of the last turn cannot be visually distinguished.

The use of a single turn of a sheet where the advanced and trailing ends abut against each other, is not desirable. During the use of the hickey rollers of the present invention the sleeves are subjected to considerable inward deflection and this develops extremely large stresses that can damage a butt joint of this type. The multi-turn arrangement or the helical arrangement withstands such deflection very effectively, and good adhesion to the core is a considerable help in this connection. At least a little pressure should be applied during the cementing to improve the adhesion, but the pressure should not be so great as to excessively distort the materials. A range of from about 1 to about 100 pounds per square inch is generally effective.

EXAMPLE II In this example a hickey roller is made from a standard inking roller in the form of a solid steel shaft one inch in diameter covered with a /8 inch thick layer of Buna N rubber of 40 durometer Shore A. Using a 36 grit carborundum wheel, the rubber cover is ground on a roll grinding lathe to a diameter 0.130 inch undersize.

The surface of the rubber roller is prepared for bonding by wiping with methyl ethyl ketone and allowing it to evaporate.

A solution of the bonding adhesive is then prepared as follows:

Parts by Weight Material Solution A Solution B High acrylonitrile uncured butadieneacrylonitrile polymer 100 Zine oxide 5 5 Sulfur 6 0 Channel black 50 50 Coumarone-indene resin M.P 25 C 25 25 Aldol-alpha-naphthylamine 5 5 Mercapto benzothiazole... 0 6 Dry methyl ethyl ketone. 800 800 Immediately prior to use, 2.5 parts of butyraldehydeaniline condensation accelerator in an equal amount of methyl ethyl ketone are added to solution B. Solutions A and B are then mixed together in equal parts and applied by spreading or brushing onto the roller. Suflicient solution should be applied so that after solvent evaporation an adhesive film about 0.003 inch thick will remain.

The substrate used as the overwrap is a polyimide fiber sheet 0.085 inch thick weighing about 9 ounces per square yard, and needle-punched from a batt of two inch long fibers that have been mechanically curled and have a denier of about 1. The sheet is not impregnated with a binder before cementing and is not given a preliminary seal coating. It is otherwise applied, impregnated, cured and finished in the same manner desscribed in Example I except that it is cut into a strip 2.4 times the diameter of the roll core and the impregnant is the one described in Example VI of U.S. Pat. 3,000,757 granted Sept. 19, 1961.

The hickey rollers described above have substrates which are essentially entirely porous throughout their depth except for those levels at which a sealing layer was applied or adhesive was used to secure the substrate to the core or to secure one layer of substrate to another. For some purposes however less porosity is desired, as for example where the hickey roller is to be very easily cleaned of all its ink. One way to reduce the porosity is to impregnate the substrate until all its pores are filled. Thus the helically wound hickey roller described above may after the curing of the last impregnant be subjected to additional impregnation and curing until it is no longer absorbent. The non-absorbent product is then ground if needed to insure cylindrical accuracy and subjected to a napping treatment by spinning it in a lathe and pressing against the entire surface fine grade emery cloth. The nap thus raised is about 5 mils high measured by the height the fiber ends project beyond the impervious body of the substrate. The filler should be less wear-resistant than the fibers so as to keep the roll operating properly even after it wears.

The following examples show additional techniques for providing low porosity:

EXAMPLE HI The roller produced in according with Example II is immersed in an aqueous dispersion of polytetrafiuoroethylene containing 50% by weight polytetrafluoroethylene particles having a size of approximately half a micron. After thorough saturation the roller is removed from the dispersion and cooled to 0 F. by placing it in a container held in an isopropyl alcohol bath containing Dry Ice. This cooling causes the water in the dispersion to freeze and the dispersion to flocculate so that the polytetrafluoroethylene particles are no longer suspended. The roller is then removed from the freeze container and exposed to the atmosphere at room temperature to permit its ice content to melt and evaporate. The impregnation treatment is then repeated, this time the impregnation being carried out in a vacuum tank with a dispersion having 50% resin, and the dried product can then be ground to finished dimensions and napped.

Printing ink does not seep into this roller although it will thoroughly permeate the nap. The hickey-picking action of such roller is still quite effective although not as good as that of the roller of Example I. The polytetrafluoroethylene has a helpful effect on the hickey-picking action since better operation is produced with the polytetrafiuoroethylene impregnant as compared with corresponding impregnation by polyurethane or plasticized polyvinyl chloride such as polyvinyl chloride plastisol. The helpful effect is believed to be due to the influence of electrostatic fields created when the roller is in operation.

EXAMPLE IV A roller like that produced in Example I but having polyamide fibers in the substrate in place of the polyethylene-terephthalate fibers, is vacuum impregnated with a solvent-free liquid cureable urethane resin cureable to a to 30 durometer Shore A hardness. A single impregnant is sufiicient to provide the desired imperviousness, after which the impregnant is cured by heating to 150 F. for six hours, the roller ground and finally napped with No. 100 aluminum oxide sandpaper to raise a nap 3 mils high.

The product of this example exhibits cleanability and hickey removal characteristics intermediate between those products of Example I and III. It is particularly useful on high speed equipment 'where cleaning ease is more important than optimizing hickey removal. Because the abrasion resistance of the fiber is substantially higher than that of the soft filler, the roller, as it wears, will continually maintain a napped surface.

It is important to note several distinctions between binders, impregnants and fillers that are used in the practice of this invention. The substrate of Example I is impregnated with a binder prior to its application on the roller. This binder is soft and gives the material considerable body during handling. This preliminary reinforcement is extremely helpful in manufacturing the invention and additionally seems to have a beneficial effect on the end product.

The binder which is impregnated into the substrate after it has been applied to the roller is considerably harder and stronger and serves the purpose of locking the fibers in place as well as preventing them from compacting during use. It also effectively cross-bonds the seams causing the finished product to appear seamless.

Fillers such as shown in Example III serve the purpose of modifying or closing the pore structure. They are used only to improve cleanability or electrostatic action and do little to strengthen the substrate.

The following is an example of a multiple-layer smooth-surfaced construction.

EXAMPLE V A rubber-covered roll core as in Example II and ten inches long has its rubber surface coated with rubber cement, and a layer of the same cement is applied to one face of a /2 inch wide substrate sheet 18 inches long. The substrate sheet is an impregnated 0.030 inch thick air-felted web of 2.5 denier shrinkable polyamide fibers 78 inch long that after felting has been thermally treated to curl the fibers. The impregnation was with 20% by weight of the binder described in Example 4 of U.S. Pat. 3,100,721. The cement-coated substrate is wrapped around the cement-covered roll core a little more than two turns, tension being applied at the end of the first turn. The outer end of the wrap is held down :with pressure-sensitive tape, and the assembly placed under pressure until the cement cures. The assembly is impregnated with the binder described in Example 1 of U.S. Pat. 3,214,290 granted Oct. 26, 1965, to increase the binder content to 40%. After curing, the roll is ground down to an overall diameter 0.100 inch larger than that of the core. This leaves an apparently seamless construction, but the impregnation is greater in the outside turn than in the inside turn of the substrate. The impregnation into the inside turn is hampered by the layer of cement between the turns, so that it takes place primarily through the narrow thickness of the sheet that connects the turns as well as 8 through the exposed edges. While such a roll can be used to pick hickeys very effectively, it is difficult to clean free of printing ink because the ink works its way into the lower turn and only washes out with difficulty. Such a roll is quite suitable however for pore filling as in Example III for instance. For such pore filling it is only necessary to make sure the edges and outer turn are filled and that they seal any residual porosity in the inner turn.

EXAMPLE VI Thickness: .100".140"

Weight: 41-49 oz./yd.

Tensile strength: 350 lbs/in.

Air permeability: 25-35 c.f.m./ft. at .05 H O This felt is slit into a strip approximately 2.5 times the roll core diameter and .wrapped carefully on the adhesive-coated roller, as in Example I. The assembly is then over-wrapped with nylon tape except that tension must not be allowed to exceed 10 pounds per inch of width. Excessivetension unnecessarily compresses the felt and causes strike-through of the adhesive.

After curing it will be noted that the felt has bonded very well to the surface of the roll core, even though the adhesive will not actually bond to the fiber material. Bond is effected through encapsulating the inner fibers and mechanically locking them in place.

Impregnation and finishing are accomplished as in Example I. It is important during grinding that the roller be turned slowly and the wheel kept clean and sharp.

The product of this example exhibits hickey-removal qualities almost comparable to that of Example I. By virtue of the polytetrafiuoroethylene fiber, it is considerably easier to clean. Similar and less costly products may be made by substituting dense felts of other fibers for polytetrafiuoroethylene. Good results have also been obtained using a 1.5 denier heat-shrunk polyester felt 0.125 inch thick weighing 2.1 pounds per square yard. The polyester felt did not produce a product as easily cleanable as the fluorocarbon felt.

FIG. 3 shows an offset printing roll assembly having a plate cylinder 30 on which the printing plate is secured as by cementing, and a train of inking rollers 31 through 38 and 41 through 44 that carry ink from an ink trough 45 and apply it to the surface of the plate. The hickey rollers of the present invention are generally used for the leading and/ or trailing plate-contacting rollers 41 or 44. The other rollers in the inking train may be the usual rubber rollers.

A train of dampening rolls 51 through 54 may also be used to moisten the plate from a water trough 56. A blanket cylinder 58 receives the ink from the inked portions of the printing plate, and transfers it to the printed sheets 60 with the help of a back-up or pressure cylinder 59.

The hickey rollers of the present invention are porous to water as well as to printing ink. If kept damp during use they will accordingly wet both the hydrophilic and oleophilic areas of the printing plate and noticeably improve the quality of the print. This improvement is emphasized by permeating the porous substrate of a roller with water before ink is applied to it. When so used, the water balance on the press becomes less critical permitting quicker start-up and less operator skill.

Another feature of the hickey rollers of the present invention is that that their operation is further improved by driving them at a rotational rate somewhat different from that required to merely roll across the plate. By gearing these hickey rollers so that their rotational. speed is 1 to 5% greater or smaller than they would have if impelled by the rolling action on the plate, they are given a wiping effect which increases the hickey removal action. Care must be taken however in that this mode of operation may cause the plate to wear prematurely.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is, therefore, to be understood that Within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed:

1. A method of making a printing roller, which method comprises wrapping a roller core with a resilient layer at least 15 mils thick of felted flexible fibers at least A2 inch long and having a denier less than three to produce a coating layer having a seam cementing the wrapped layer in place, impregnating the layer with a resilient binder to fill its pores, and grinding the surface of the impregnated layer to blur the seam and leave the surface cylindrical, smooth and with a porous outer nap of fiber ends.

2. The method of claim 1 in which the impregnation crossbonds the seam.

3. A method of making a printing roller, which method comprises cementing around the entire cylindrical surface of a rubber-covered roller a resilient felted sheet 15 to 80 mils thick of crinkled fibers of the class consisting of polyamide, polyester, polyacrylonitrile and polyimide fibers having an uncrinkled length of at least about /2 inch and a denier less than 3, impregnating the sheet to fill its pores and bond the fibers together, grinding the surface of the cemented impregnated sheet to leave it cylindrical, and raising an outer porous nap of fiber ends on the ground surface.

4. The method of claim 3 in which the rubber cover on the roller has a surface with a hardness less than 50 Shore A, the cementing is with a resilient adhesive, the felted sheet is a needle-punched sheet and the impregnating includes an impregnation with a resilient binder that is less wear-resistant than the fibers.

5. A method of making a hickey roller which method comprises the steps of helically wrapping around a mandrel a porous sheet of felt made of fibers at least about /2 inch long and having a denier less than 3, the sheet being at least 15 mils thick, carrying out the wrapping with a settable adhesive stratum between the sheet and the mandrel and with the helical sheet edges abutting, compressing the wrapped sheet about the mandrel until the adhesive is fully set, filling the pores of the sheet and impregnating it with an elastomeric binder that strengthens it and grinding the surface of the adhered sheet to leave it cylindrical, smooth and with an outer nap of fiber ends porous to printing ink.

6. The method of claim 5 in which the mandrel has a rubber surface, and the adhesive is flexible.

7. A method of making a hickey roller which method comprises the steps of wrapping around a mandrel a plurality of overlapping turns of a porous sheet of felt made of fibers at least about /2 inch long and having a denier less than 3 to build up a total wrap thickness of at least mils, carrying out the wrapping with a settable adhesive between the sheet and the mandrel as well as between overlapping portions of the sheet, compressing the wrapped sheet around the mandrel until the adhesive is fully set, then filling the pores and impregnating at least the outer turn of the wrapped sheet with a binder that strengthens it, and grinding the outer portion of the 10 wrapped sheet to leave it cylindrical, smooth and with at least an outer map of fiber porous to printing ink.

8. The method of claim 7 in which the adhesive and binder are flexible.

9. A method of making a printing press roller which method comprises the steps of Wrapping around a mandrel a bonded sheet of felt made of fibers at least /2 inch long, the sheet being at least 15 mils thick, carrying out the wrapping with a settable adhesive stratum between the sheet and the mandrel to cement the wrapped sheet in place, grinding the surface of the cemented sheet to leave it cylindrical, and raising an outer nap of fibers on the ground surface.

10. The method of claim 9 in which the sheet is helically wrapped around the mandrel with the helical edges of the sheet abutting, and the cemented sheet is impregnated with a soft yieldable binder before it is ground.

11. The method of claim 10 in which the sheet is also impregnated with polytetrafluoroethylene.

12. The method of claim 10 in which the mandrel has a rubber surface, and the adhesive is flexible.

References Cited UNITED STATES PATENTS 1,789,244 l/193l McCOllurn. 2 775,195 12/1956 Martin 101148 2,804,678 9/1957 Rockofl 29-121 2,843,883 7/1958 Rockoff 19-143 3,100,721 9/1961 Holden 117-135.5 3,147,698 9/1964 Ross 101149.2 3,229,351 1/ 1966 Peterson et a1 29129.5 3,284,274 11/1966 Hulslander 161--159 3,293,728 12/1966 Hill 29132 3,326,740 6/1967 Hand 161170 3,345,942 10/1967 Meltz 101348 3,460,222 8/1969 Mitchell, Jr. 29l20 2,152,612 3/1939 Tischer 156171X 2,482,702 9/ 1949 Billmeyer 156--171 3,338,163 8/1967 DeMaria et al. 161-160X 2,812,007 11/ 1957 Touchett et al. 15660X 3,390,762 7/1968 Mernieks 161-160 3,467,009 9/ 1969 Ross 101216X FOREIGN PATENTS 495,159 1l/193 8 Great Britain 29-130 892,984 4/ 1962 Great Britain 29-132 1,008,017 11/ 1965 Great Britain. 1,259,931 3/ 1964 France. 1,878,038 6/ 1963 Germany. 1,967,743 12/1966 Germany. 1,977,434 1 1/ 1967 Germany.

OTHER REFERENCES German Auslegeschrift, No. 1,135,930, April 1960, Beutel.

German Auslegeschrift, N0. 1,179,567, April 1959, Retzerfeld et a1.

German Auslegeschrift, No. 1,242,643, June 1967.

SAMUEL W. ENGLE, Primary Examiner T. H. WEBB, Assistant Examiner US. Cl. X.R.

UNITED STA'IES PA'I I 'INT OFFICE CERT].FICATE OF CORRECTION Patent NO. 37 5 9 L'255 Dated July 20, 1971 mnmenemmmoen It is certified that error appears in the above-identified patent and that said Letters Patent: are hereby corrected as shown below:

' Column 1, line 32, after "plate" --to-- should be inserted? line 36, "had" should be --hae--.

Column 6, line 54, "according" should be --accor'donce--. Column 9, line 15, tbere should be a comma after "seam".

line 50, there should be a comma after "it".

Column 10, line 2, after "fiber" -ende-- should be inserted.

Column 10, line 2, "map" should read nap Signed and sealed this 5th day of December 1972.

(SEAL) Attest:

EDWARD M.FLETCHER- JR; ROB Attesting Officer ERT GOTTSCHALK Commissioner of Patents 

